The present disclosure relates to a motor and a method for starting the same, and more particularly, to a synchronous motor and a method for starting the same.
Motors are devices in which a rotor is rotated by an external power. Among the different types of motors, a synchronous motor is a motor in which a speed of a rotor follows a frequency of an external power. The rotor is rotated by applying an appropriate power to a stator according to a position of the rotor.
A synchronous motor is started by forcibly aligning the rotor to a desired position even though a position of the rotor is not known in the beginning. A representative method is to apply power strongly to one specific phase of three phases to place the rotor to the center of a coil to which the power is applied.
However, such a forced alignment method can align the rotor to an accurate position without alignment error of the rotor when no external load is applied to the rotor, but in many cases, the forced alignment is not achieved when an initial load is applied to the rotor.
If a scroll compressor is given as an example, even when the operation of the scroll compressor is in a stationary state, a fluid received in a compression space between an orbiting scroll and a fixed scroll can be under higher pressure compared to a fluid received in the other space. In this case, even though power is applied to any one of the three phases in order to forcibly aligning the motor, an electromagnetic force of the motor may be smaller than a force for compressing the fluid received in the compression space. In this case, the rotor is not aligned to an initial set position.
If the above-described state is mistaken for the achievement of the alignment and thus the motor starts to operate, the result is malfunctioning of the motor, damage of the compressor, and damage of electronic devices in the compressor.